Born in the brothels of Buenos Aires, tango embodies, perhaps more than anything else, the brooding sensuality and passion of the Argentine people. A musical and dance genre which, at its best can evoke the eroticism of a Klimt painting or a Moore sculpture, tango is currently enjoying a thrilling revival in Buenos Aires. And this August the city celebrates its 10th annual World Tango Festival.

Born in the brothels of Buenos Aires, tango embodies, perhaps more than anything else, the brooding sensuality and passion of the Argentine people. A musical and dance genre which, at its best can evoke the eroticism of a Klimt painting or a Moore sculpture, tango is currently enjoying a thrilling revival in Buenos Aires. And this August the city celebrates its 10th annual World Tango Festival.

An estimated 400,000 festival-goers from Argentina and abroad are expected to attend the festival, which gets underway on 13 August and runs for 18 days. Billed by its organisers as "the world's biggest tango extravaganza", it is, in fact, two events in one. It starts with La Festival -a nine-day celebration of tango shows and recitals, classes and milongas (dances), book signings and film screenings at venues across the city-before morphing into the Mundial de Tango, the Tango World Championship, which pits the world's finest tango dancers against one another.

"August is the month of tango," says City Minister for Culture, Hernán Lombardi, whose organising team have orchestrated an opening ceremony that could put several Olympic Games committees to shame. Its highlight is a massive open-air milonga, which will see over ten thousand tangueros pirouetting across the cobbled streets of central Buenos Aires. Organisers hope it will set the tone for an 18-day marathon that will return tango to centre stage in the Argentine capital for the first time since its 1920s heyday.

Participation in the opening milonga, like all of the festival's events, is free of charge. Lombardi is keen to stress too that this festival is not only for tango diehards, but for anyone with an embryonic interest in the genre. Classes and milongas will take place daily at venues across the city and cater to everyone from the absolute beginner to the serious tanguero. It is simply a case, says Lombardi, of checking the festival website to see what's on where and when.

By stepping onto the polished floors of this city's tango salons, festival-goers trace a genre whose genesis lies in the 1880s and Buenos Aires' impoverished southern barrios (districts). In his book Tango! The Dance, the Song, the Story! author Simon Collier says it was in the barrios near the port at La Boca that compadritos, delinquent immigrants, frequented the dances of African Argentines - the descendants of freed slaves. There, the compadritos witnessed the athletic leaps and suggestive pauses of African dances, which they later parodied at the brothel dances of the southern slums. When the compadritos mockingly meshed these extravagant gestures with the more static embraces of the European dances then popular in Buenos Aires, tango emerged.

Tango made its way from the southern brothels to the bordellos of Argentina's social elite, and later to the city's ballrooms, where tango's lascivious contortions and delinquent origins at once scandalised and thrilled high society. Musicians fitted rhythms and melodies to tango's complex dance steps. Later, tango singers, led by Carlos Gardel, wedded melancholic lyrics of urban alienation and unrequited love to tango's florid musical notes.

Gardel stood at the fore of tango's 1920s golden age and his baritone voice will be heard across Buenos Aires throughout the festival, whose dramatic climax is the Tango World Championship final, held on the festival's final day in front of an arena audience of 8,000 spectators.

For most Argentines tango, and by extension its annual festival runs deeper than just song and dance. "The tango is about passion, sentiment and love," says Lombardi. "And we are passionate people. This festival celebrates something which is part of our identity."